Hypoxic Ischemic Encephalopathy (HIE)
HIE results from inadequate oxygen supply to the brain and is a major cause of perinatal death and subsequent neurological disability. Ideally, personnel skilled in neonatal resuscitation should be present at every high-risk delivery.
In the newborn period, HIE is associated most often with diminished fetal oxygenation due to perinatal events, though it can also result from severe cardiovascular or pulmonary insufficiency in the neonatal period. The fetus may be subject to intrauterine hypoxia due to uteroplacental insufficiency with reduced oxygen delivery to the fetus. Conditions such as abruptio placentae, maternal hypertension, or having the umbilical cord wrapped around the neck may increase the risk of oxygen deprivation.
In practical terms, neonatal encephalopathy due to hypoxia or ischemia is a greater risk in babies with a 5-minute Apgar score of 0 to 3 and with an arterial pH of 7 or less. Complications include neurological injury but also cardiac, renal, intestinal, and hepatic damage. Neurological damage may be reduced in the full-term baby by immediately instituting hypothermic management for the first 72 hours of life.
